1. Field of the Invention
This invention relates to a method of repairing large rotating machinery such as grinding mills in the field, thereby avoiding the high cost of returning the parts to the factory or a service facility for repair.
2. Description of the Prior Art
Large rotating equipment such as a grinding mill is frequently made of several parts bolted together. These parts may be as large as 36 feet in diameter and 160 feet long weighing over 150 tons. Individual parts such as a shell could weigh up to 100 tons. These parts are usually joined by bolts extending through circumferentially spaced hole in radially extending flanges. After years of use the joints between the parts wear due to friction or erosion and have to be repaired to avoid a failure of the joints that could destroy the machine. In the past when a weakening of the joint was detected, the parts were disassembled and returned to a service shop or the factory for repair. The repair consisted of machining the worn surfaces of the facing flanges to produce a smooth surface to abut the mating surface of the other flange to provide a seal and a maximum transfer of forces from the driving part of the machine to the driven part. The dismantling and shipping of these massive parts to service centers was both time-consuming and expensive. Further, the use of specialized equipment at the site to machine the flange surfaces, if available, is very expensive.